1. Field of the Invention
The present invention relates generally to alarm systems and, more specifically, to a portable alarm system including a remote control alarm activator able to monitor movement within a predetermined range from a central unit and contact a central station upon detecting an emergency situation.
2. Description of the Prior Art
Numerous types of alarm systems have been provided in the prior art. For example, U.S. Pat. Nos. 3,594,768; 4,810,998; 5,463,595 and 5,760,687 all are illustrative of such prior art. While these units may be suitable for the particular purpose to which they address, they would not be as suitable for the purposes of the present invention as heretofore described.
A motion detecting device utilizing an ultrasonic radiator and an ultrasonic microphone in which the microphone is electrically connected to an audio detector, and the output of the audio detector is converted into pulses. Pulses having a repetition rate greater than a threshold value are accumulated and utilized to trigger a bistable multivibrator. The output of the multivibrator passes through a time delay device to an alarm, and the unit is provided with an electronic switch for deactuation during the period of time delay.
The interruption demonstrating and multi-phase burglar alarm system is started by signals from 2 or more than 2 detectors amplified and inputted into an interruption demonstrating circuit. By an outside interruption signal, the sensitivity will be properly adjusted. The device also has a multi-phase to detect in single or adjacent multiple areas. The two detectors will be activated within a pre-set period or will not trigger the alarm. The controlling circuit will reset the device in case of any improper or mistaken signals, thereby providing continuous protection and preventing false alarms.
A security system suitable for use in monitoring property at an outdoor site that includes a portable housing that supports a motion detector for sensing motion within a detection zone. The security system further includes an ultrasonic transducer and several alarm generators capable of repelling a human intruder, including a high intensity illumination source, high decibel siren, strobe light and a speaker for transmitting a prerecorded message. When an intrusion is initially detected by the motion detector, the ultrasonic transducer is activated to emit an ultrasonic signal that is irritating to nonhuman animals, thus clearing the detection zone of nonhuman intruders. If after sounding of the ultrasonic transducer motion is still detected, one or more of the alarms is activated. Additionally, an automatic telephone dialer may be included in the system and activated by the system as another type of alarm, in response to detected intrusion. The system is integrated within the portable housing and is resistant to false alarms, making it suitable for use in monitoring property stored at an outside site. A method for utilizing the security system to protect property is also disclosed.
The signal delivered by a Doppler sensor is treated after amplification, filtering and digitization by means for determining the global energy of the digitized signal, autocorrelation test means for showing up a dominant frequency, a filter for rejecting that frequency, comparators for eliminating signals having energy less than a threshold, a filter for isolating a particular frequency band, and means for intercorrelation with a reference signal held in memory.